Year	Percent
1990	22.327
1991	23.054
1992	23.884
1993	24.691
1994	25.46
1995	26.26
1996	26.449
1997	26.909
1998	27.387
1999	27.856
2000	28.56
2001	29.038
2002	29.375
2003	29.721
2004	30.267
2005	30.887
2006	32.346
2007	33.665
2008	34.893
2009	35.763
2010	36.29
2011	36.613
2012	37.146
2013	37.364
2014	37.427
2015	37.563
2016	37.302
2017	37.184
2018	37.058
2019	36.938
2020	36.825
2021	36.605
2022	36.393
2023	36.201
2024	36.038
2025	35.905
2026	35.715
2027	35.556
2028	35.442
2029	35.381
2030	35.374
